Optimization of corrosion inhibition of essential oils of Alpinia galanga on mild steel using Response Surface Methodology

The use of plant extracts as corrosion inhibitors has gained prominence as replacement for synthetic organic compounds. The plant natural products have been found to be effective, cheap and eco-friendly anticorrosion agents. Corrosion inhibitions of essential oils of Alpinia galanga were investigated on mild steel in hydrochloric acid solution using weight loss method. The interactive effects of inhibitor concentration, temperature and time were optimized for maximum response of inhibition efficiency using Response Surface Methodology with Central Composite Design. The optimum inhibition efficiency of 88.5% at 775 ppm of inhibitor concentration, temperature of 320.4 K and reaction time of 3.75 hours was accomplished. The effectiveness of the inhibitor was also supported using scanning electron microscopy. The mechanism of interaction of both the inhibitor on mild steel surface was found to conform to the Langmuir adsorption isotherm

Chiral Modulations in Curved Space I: Formalism

The goal of this paper is to present a formalism that allows to handle four-fermion effective theories at finite temperature and density in curved space. The formalism is based on the use of the effective action and zeta function regularization, supports the inclusion of inhomogeneous and anisotropic phases. One of the key points of the method is the use of a non-perturbative ansatz for the heat-kernel that returns the effective action in partially resummed form, providing a way to go beyond the approximations based on the Ginzburg-Landau expansion for the partition function. The effective action for the case of ultra-static Riemannian spacetimes with compact spatial section is discussed in general and a series representation, valid when the chemical potential satisfies a certain constraint, is derived. To see the formalism at work, we consider the case of static Einstein spaces at zero chemical potential. Although in this case we expect inhomogeneous phases to occur only as meta-stable states, the problem is complex enough and allows to illustrate how to implement numerical studies of inhomogeneous phases in curved space. Finally, we extend the formalism to include arbitrary chemical potentials and obtain the analytical continuation of the effective action in curved space.Comment: 22 pages, 3 figures; version to appear in JHE

Establishment of the temperature field on surface metal wheels worn when the temperature in part near exceed the temperature Curie point

Розроблено математичну модель для визначення джерел нагріву, коли температура на торці колеса перевищує температуру Кюрі, яка необхідна для одночасного нагрівання спрацьованого металевого колеса по всій робочій поверхні з метою нарощування його методом заливки рідкого металу в тигель і схоплення його з робочою поверхнею колеса, що дозволяє значно підвищити продуктивність і якість процесу та зменшити матеріальні й трудові затрати в порівнянні з існуючими методами відновлення металевих коліс.A mathematical model to determine the sources of heat when the temperature at the wheel ends exceeds the Curie temperature which is necessary for the simultaneous heating of the metal wheels worn throughout the working surface to increase it by pouring molten metal in the crucible and its grip on the wheel working surface that can significantly improve productivity and process quality and reduce material and labor costs compared with existing methods of recovery of metal wheels